It comes as former Australian Defence Force chief Angus Houston is expected to be appointed to help coordinate the international search effort.

While numerous objects were sighted by surveillance planes and some recovered by vessels on the scene, the Australian Maritime Safety Authority (AMSA) reported that none of the closely scrutinised debris were from the missing Malaysia Airlines aircraft.

A flotilla of ships searched for more objects identified by military aircraft as possible wreckage of MH370 as an ever-expanding multinational effort to locate the missing Malaysia Airlines passenger jet stepped up a gear.

Late on Saturday, a Chinese surveillance plane reported it found three more objects - white, red and orange - in the new search waters, Chinese state media reported.

As new aircraft, ships and a team of navy divers prepared to join the search, the head of New Zealand's Defence Force, Air Vice-Marshal Kevin Short, said the debris first sighted by its P3 Orion aircraft on Friday was between half a metre and one metre in size.

Most of the 11 objects were rectangular in shape, although there was another that was orange and resembled a shipping buoy.

Most were found in a relatively small area and sonar buoys had been dropped by the aircraft to assist ships who would be tasked to identity them.

Two Chinese ships, Haixun 01 and Jinggangshan, and HMAS Success arrived in the search zone, which was shifted 1100 kilometres north-east on Friday after fresh analysis of radar, satellite and MH370's performance capability led Australian authorities to conclude the plane had not flown as far as originally thought.

Four more ships were due to arrive late on Saturday in a search area 1800km west of Perth and 319,000 square kilometres in size, almost 50 per cent bigger than Victoria and four times larger than the previous search zone.

While the weather was clear on Saturday morning, it deteriorated in the afternoon.

''We should not underestimate the difficulty of this work,'' Prime Minister Tony Abbott said on Saturday. ''It is an extraordinarily remote location. These are inhospitable seas. It's an inaccessible place. We are trying to find small bits of wreckage in a vast ocean and while we are throwing everything we have at it, the task goes on.''

Air Vice-Marshal Short said parts of the aircraft would be floating in the sea, such as fuel tanks from wings, composite materials and plastics.

"The only way to really identify them is to get them on board the ship," he told Bloomberg.

Even then, it could be necessary to get the objects back to Perth for analysis "unless there is something very obvious in what they pick up".

As it entered its fourth week, the search effort was augmented by the arrival of two Malaysia C-130 transport planes, which landed at RAAF Base Pearce near Perth on Saturday.

The frigate HMAS Toowoomba has been diverted from its task of scouring Australia's northern reaches for asylum seeker boats and will join soon. It arrived at Garden Island naval base near Perth on Saturday and will take on a new crew that will include a contingent of navy divers who will be required to secure any found items.

HMAS Toowoomba will also carry a Seahawk helicopter.

On Sunday, the Australian navy vessel Ocean Shield is also expected to arrive near Perth and will take on board a towed pinger locator and a team of US military personnel who will operate the machine. It is designed to pick up any signal from the beacon of MH370's flight recorder, known as the black box.

Its beacon is expected to run out of batteries in about nine days. This adds urgency to the search as the black box, which records cockpit conversations and flight data, is the key to learning what happened to the missing aircraft, which had 239 passengers and crew.

ADV Ocean Shield will also carry a Bluefin-21 unmanned submersible drone equipped with sensors and cameras. This can search the ocean floor for the black box even after its beacon has shut down.

While the new search area is remote and enormous, it presents two advantages over those further south. The ocean, at between 2000 and 4000 metres, is shallower. Also, the weather is generally calmer than the ''roaring forties'' between Australia and Antarctica.

Commodore Peter Leavy, the overall military commander of the search effort, said: ''This is a very, very big operation ... Normally a military exercise involving different nations is the result of a lot of planning. Something like this ... we had to come together very quickly and just get on with the job.''